Emile andreoli



j (No Model.)

. E. ANDREO-LI. APPARATUS FOR INDIREGT E'LEGTROLYSIS. No. 565,953. Patented Aug. 18, 1896.

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A 3211 FFM 17 I A g UNITED STATES PATENT OFFIGE;

EMILE ANDREOLI, OF LONDON, ENGLAND.

APPARATUS FOR IN-DIRECT IELECTROLYSIS.

SPECIFICATION forming part of Letters Patent No. 565,953, dated August is, less.

Application filed April 9,1895. derial No. 545,080. (110 model.) Patented in Belgium september 25, 1894, No. 111,942, and in England March 8, 1895, No. 4,939.

To all whmn it concern.-

Be it known that I, EMILE ANDREQLI, a

citizen of France, residing at London, in the county of Surrey, England, have invented certain new and useful Improvements in Apparatus for Indirect Electrolysis, (patented by me in Belgium September 25,1894,No. 111,942, and in England March 8, 1895, No. 4,939,) of which the following is a full, clear, and exact description.

This invention relates to a new process of electrolysis which I will call indirect electrolysis.

According to my invention the anode and cathode to which the electric generator is connected are situated in compartments formed by two porous partitions and which contain suitable electrolytes, and the solution to be treated by the indirect electrolysis contained in or passed through a compartment situated between the anode and cathode compartments.

The indirect electrolysis takes place in the central compartment, which contains metal, carbon, or the like in the form of plates, gauzes, pieces, or in any suitable form and of a character in accordance with the solution, and these metal plates, gauzes, or pieces, or the like are not connected with either the cathode or anode in the adjoining compartments nor with the poles of the electric generator.

In the accompanying drawings, Figure 1 is asectional View of my electrolytic tank. Fig. 2 is a side view-of one of the plates in the middle compartment. Fig. 3 is a conventional view of a circulating system with a series of tanks, and Fig. 4 is a section of a modified form of tank.

I will give two illustrations of the application of my invention: first, to the reduction of a bisulfite-of-sodium solution to the state of hydrosulfite of sodium, which is a very powerful bleaching agent; secondly, to the precipitation and deposition of gold or silver, &c., from their solution, from which also the other applications of the invention will be understood.

In the first case in the positive compartment at of the tank the electrolyte a will be, for instance, a caustic-potash solution, and in the negative compartment bit will be a chlorid-of-sodium solution b. I may use other convenient electrolytes. The liquid in the central compartment 0 is a solution of bisulfite of sodium 0, in which zinc or other suitable plates d, pieces, gauzes, or the like are immersed, not connected with the anode a and cathode I) nor with the electric generator. As soon as the current passes through the tank the solutions in the positive and negative compartments are decomposed in the usual manner and the bisulfite of sodium is transforme into hydrosulfite of sodium.

' The bisulfite solution may .fiow from a reservoir e successively through several such tanks connected in series by suitable pipes or passages f and be pumped back to the reservoir, which is used as a bleaching-tank, from which it passes again through the central compartment c of the electrolyzer, Where it recovers its bleaching properties. The solution may be used over and over again before it requires an addition of fresh bisulfite of sodium to maintain its strength. Other liquids can be submitted to the indirect or secondary electrolysis, and the anolyte and catho-- lyte, as well as the metal of the plates, gauzes, or pieces, or the like, which dip in the central compartment, may be varied asconvenient.

I will now describe the precipitation or deposition of gold or other metals.

In the usual electrodepositing-tanks there are two electrodes-via, an anode and a cathode. Gold, silver, or other metal is deposited on the cathode, and both the anode and the cathode are dipped in the metallic solution.

In carrying out my invention as applied, for example, to the obtainment of gold from" its solutions the metallic plates d or perforated sheets, gauzes, pieces, or the like on which the metal will be precipitated are placed in the central compartment between the positive and negative electrodes, which work in any convenient electrolyte in their respective compartments, as before.

There is no metal precipitated on the cathode, as in the ordinary art of electrodeposition of metals; but the gold or silver or other metal is precipitated on the said sheets, gauzes, pieces, or the like, which, if in the form of plates or sheets, are preferably perforated and maybe made of lead, zinc, silver,

or other suitable metal or material and be disposed vertically or horizontally or in other convenient position over or near each other in the central compartment, and which are not connected in any way to the anode or cathode in the next compartment nor to the poles of the dynamo or electric generator.

The indirect electrolysis precipitates the gold on the whole and on the two sides of the perforated sheets, plates, gauzes, pieces of metals, or the like which are in the central compartment and which adjoin the positive compartment.

The solution containing'gold is in or passes through the central compartment, in which the said metallic plates, gauzes, or pieces or the like are placed and Where the indirect electrolysis is set up under the influence of the true anode and cathode, which, each in its respective compartment and in any convenient electrolyte, work independently. This indirect electrolysis in the central compartment precipitates or deposits 011 the plates, pieces, or gauze's immersed in the solution containing the gold until the strong or weak metallic solution is practically exhausted.

I do not confine myself 'to zinc or lead perforated sheets or gauzes. I can use any convenient metal as a substratum for the precipitation of the metal. For instance, I may have at the bottom of the central compartment a layer of mercury, as g, not in contact with the .plate which is standing close to the diaphragm of the negative compartment. In this layer of mercury, which is about one-half inch or lessdeep, the quantity of mercury being proportionate to the quantity of gold to be precipitated, dip the bottom of as many amalgamated coarse gauzes d or perforated sheets of copper, iron, or other convenient metal or alloy as the width of the compartment allows me to place vertically, and by indirect electrolysis the circulating solution yields its gold to suit amalgamated wiregauzes or to the mercury layer with which it is in intimate contact.

The mode of arrangement of the perforated sheets or plates, gauzes, or pieces of metal or the like conducting material in the central compartment may be Varied according to circumstances, but it must be understood that the more the central compartment contains of such sheets, plates, gauzes, pieces, or the like the better and quicker the deposition of gold on their surface will be. effected by the indirect electrolysis. It is advisable to avoid the contact of the plates or the like disposed on the side of the porous diaphragm of the positive compartment with a plate or the like or plates on the side of the porous diaphragm of the negative compartment.

Having thus particularly described and ascertained the nature of this invention and the manner in which it is to be performed, I declare that what I claim is- For the indirect electrolysis of solutions, a tank divided into three successive compartments by two porousdiaphragms, the middle compartment containing the solution to be subjected to the indirect electrolysis and also containing a series of perforated plates or their equivalent, and the end compartments containing any other suitable solution and respectively positive and negative electrodes, the plates in the middle compartment, being disconnected from the said electrodes'and from a source of electricity and adapted to have precipitated upon them one of the ingredients contained in the solution in the middle compartment, substantially as described.

In testimony whereof I subscribe my signature in presence of two witnesses.

EMILE ANDREOLI.

Witnesses:

ALFRED NUTTING, A. NIoN. 

